The invention is situated in the field of materials handling technology and concerns a method and a device in accordance with the generic terms of the corresponding independent claims. Method and device serve for conveying piece goods, i.e. a large number of articles being conveyed and held and if so required being processed individually or in small groups and being at least similar to one another in such a manner, that they are able to be held and conveyed with the same holding/conveying means. The method according to the invention and the device according to the invention serve in particular for loading the holding/conveying means with articles and/or for unloading articles from the holding/conveying means.
Holding/conveying means for conveying individual articles in a held manner are e.g. grippers which are matched to the articles, which are arranged on a conveying chain at regular distances and which are equipped for gripping an article each at a loading point, for conveying the article along a conveying track and for releasing the article at an unloading point. During conveyance or during an interruption of conveyance, the articles held and conveyed by the grippers can also be processed usually being held in the correct processing position by the grippers, the processing being carried out usually in a regularly clocked manner.
Holding/conveying means for held conveyance of piece goods can also be independent of one another and individually displaceable along a corresponding rail system. In such systems for conveying piece goods, processing operations can be carried out in a regularly clocked manner, wherein the holding/conveying means are clocked into the processing station. It is, however, also possible to guide the holding/conveying means into the processing station with individual distances between them and to activate the station for a processing operation only if a holding/conveying means carrying an article to be processed is detected.
It is the object of the invention to create a method and a device, with which holding/conveying means can be loaded with an article each and the article can be unloaded during essentially continuous or if so required stepwise conveyance, wherein the holding/conveying means are independent of one another or are connected to one another at regular or variable distances. Loading and/or unloading shall not comprise any unguided movement of the articles, in particular in such a way, that the position of every loaded article is exactly defined relative to the holding means. The method according to the invention and the device according to the invention are to be suitable in particular for the conveyance of articles with different formats in such a manner, that a change-over from one article format to another article format can be effected with as little change as possible or with no change of method and device. Nonetheless, method and device are to be simple and applicable for as many different holding/conveying means and applications as possible and the device in accordance with the invention is to be implementable with as few moving parts as possible.
This object is achieved by the method and by the device as defined in the corresponding independent claims.
In the method according to the invention, holding/conveying means are conveyed through a loading and/or an unloading zone. In parallel to the holding/conveying means and in synchronism with them, article guides are conveyed through the loading/unloading zone also, i.e. with the same distances from each other and with the same speed as the holding/conveying means and in such a manner, that one article guide and one holding/conveying means are stationary relative to one another and aligned to one another. During conveyance through the loading/unloading zone, each article guide remains assigned to the one holding/conveying means and articles or groups of articles are pushed out of article guides into holding/conveying means for loading or from holding/conveying means into article guides for unloading, wherein the displacement of the article is carried out substantially transverse to the conveying direction. For the displacement of the articles e.g. article pushers assigned to one article guide each are provided which article pushers carry out a displacement movement substantially perpendicular to the conveying direction in the loading/unloading zone. For guiding the displacement of the articles from the holding means to the article guide and vice-versa in a stable manner and with an essentially unchanged spatial position of the article, it is important, that not only the article guides are designed as guides essentially unchanging in the displacement direction, but also the holding means. This means that the holding means have at least within the zone of the displacement path a constant guide cross-section perpendicular to the displacement direction.
Advantageously, the holding/conveying means are conveyed through the loading/unloading zonexe2x80x94independent of how they are conveyed in other zones of the conveying systemxe2x80x94at regular distances between one another and advantageously mechanically coupled with the article guides and article pushers, all being driven by the same drive. It is, however, also possible to convey the holding/conveying means through the loading/unloading zone at irregular distances from one another and to couple at the entrance of this zone one article guide and one article pusher respectively to each holding/conveying means and to maintain this coupling up to the end of the zone.
In a loading zone, for example, the following process steps are carried out:
Supplying open holding means, article pushers and article guides to the loading zone, every article guide bringing along an article;
Conveying in a synchronous manner, articles guides, article pushers and holding means in sets of one of each through the loading zone and simultaneously pushing articles from article guides into open holding means by moving the article pushers essentially perpendicular to the conveying direction;
Closing the holding means at the exit of the loading zone;
Conveying article guides, article pushers and holding means away from the loading zone, every holding means holding an article.
In an unloading zone, for example, the following process steps are carried out:
Supplying article guides, article pushers and holding means in sets of one of each to the unloading zone, each holding means holding an article;
Opening the holding means at the entrance to the unloading zone;
Conveying article guides, article pushers and holding means in synchronism through the unloading zone and simultaneously pushing articles out of the open holding means into article guides by moving the article pushers essentially perpendicular to the conveying direction;
Conveying open holding means, article pushers and article guides away from the unloading zone, each article guide carrying an article along with it.
The article guides and article pushers advantageously are designed in such a manner, that gravity holds the articles in a position defined by these means such that further movable parts are not necessary.
If the holding means, article guides and article pushers are suitably designed, the method in accordance with the invention can also serve for loading a small group of articles onto a holding means or for unloading it from the holding means.